JP2006345784A - Method for raising filter-feeding bivalve, system for raising the filter-feeding bivalve, method for purifying brackish water using the filter-feeding bivalve, and system for purifying the brackish water using the filter-feeding bivalve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently raising a filter-feeding bivalve, using a system for raising the filter-feeding bivalve and, especially, capable of preventing the filter-feeding bivalve from suffering weight loss in summer, and to provide a method for efficiently purifying brackish water, using a system for purifying the brackish water capable of effectively exhibiting a water quality-purifying function inherent in the filter-feeding bivalve. <P>SOLUTION: In this method, a Japanese corbicula clam is raised by flowing the brackish water through a water channel made of concrete or covered with a water barrier sheet. It is preferable that sand is not laid on the water channel as a bottom material, a depth of a deposit deposited in the water channel is made to be not more than several cm, and a depth of the water in the water channel is made to be shallow. The brackish water is effectively purified, by applying the method to the system for purifying the brackish water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for breeding filtered edible bivalves and a breeding system for filtered edible bivalves, and more particularly, to a breeding method for preventing summer thinning of filtered edible bivalves. Furthermore, this invention relates to the purification method of brackish water using a filter edible bivalve, and the purification system of brackish water using a filter edible bivalve.

Filtered edible clams such as Yamatoshijimi are fed by filtration, suspended in water such as phytoplankton and digested in the body, fixing nutrients to the shell and soft body, and at the same time partially It is known to have the property of being deposited as feces or pseudofeces (for example, see Non-Patent Document 1). Water quality purification of brackish water has been carried out using the water quality purification function of such a filter edible bivalve (see, for example, Non-Patent Document 2).
Dame RF (1996) Ecology of Marine Bivalves; An Ecosystem approach, 254pp, CRC Press, Florida Morihiro Aizaki, Mitsuko Morioka, Kunio Kiso; Basic research on water purification in brackish water using Yamato Shijimi, water and drainage, vol40, NO.2 (1998)

  However, sediments such as feces and pseudofeces excreted by the filter edible bivalve deteriorated the sediment environment and adversely affected the growth of the filter edible bivalve itself. This deterioration of the sediment environment was particularly noticeable in the summer. As a result, the water purification function of the filter edible bivalve has not been demonstrated well during the summer. In addition, filterable bivalve molluscs generally have the habit of diving and living in sand, so it is difficult to separate sediment from sand and remove sediment from sand. there were.

  Therefore, an object of the present invention is to provide a method for efficiently raising a filter edible bivalve and a system therefor. Furthermore, it aims at providing the method and system for purifying brackish water efficiently through the method.

  The breeding method for preventing the summer thinness of the filter edible bivalve according to the present invention includes a step of breeding the filter edible bivalve while flowing brackish water into the waterway. Here, the deposit deposited in the water channel is preferably several cm or less, for example, 3 cm or less. Moreover, it is preferable to make the depth of the water channel shallow. For example, the depth of the water is preferably 10 cm or less, and more preferably 5 cm or less.

  In addition, the water channel is made of, for example, concrete or covered with a water shielding sheet, and further, sand is not laid as a bottom material.

  In addition, the filtered edible bivalve is, for example, Yamatoshijimi.

  Furthermore, the breeding method of the filter edible bivalve according to the present invention includes a step of breeding the filter edible bivalve while flowing brackish water into the waterway. Here, the deposit deposited in the water channel is preferably several cm or less, for example, 3 cm or less. Moreover, it is preferable to make the depth of the water channel shallow. For example, the depth of the water is preferably 10 cm or less, and more preferably 5 cm or less.

  In addition, the water channel is characterized in that sand is not spread as bottom sediment, and is further characterized in that it is made of, for example, concrete or covered with a water shielding sheet.

  In addition, the filtered edible bivalve is, for example, Yamatoshijimi.

  Furthermore, the method for purifying brackish water according to the present invention is characterized by including a step of passing brackish water through a channel for breeding a filter edible bivalve. Here, the deposit deposited in the water channel is preferably several cm or less, for example, 3 cm or less. Moreover, it is preferable to make the depth of the water channel shallow. For example, the depth of the water is preferably 10 cm or less, and more preferably 5 cm or less.

  In addition, the water channel is made of, for example, concrete or covered with a water shielding sheet, and further, sand is not laid as a bottom material.

  In addition, the filtered edible bivalve is, for example, Yamatoshijimi.

  Furthermore, a system for breeding a filter edible bivalve according to the present invention comprises a water channel for breeding the filter edible bivalve having an inlet for brackish water inflow and an outlet for discharging, and the inlet from the inlet. Supply means for supplying brackish water to the water channel, and the supply means has adjusting means for adjusting the flow rate of the brackish water supplied to the water channel. Here, the adjusting means reduces the depth of water in the water channel. At this time, the depth of water is preferably 10 cm or less, and more preferably 5 cm or less.

  The water channel is made of, for example, concrete or covered with a water-impervious sheet, and further, sand is not laid as a bottom material.

  In addition, the filtered edible bivalve is, for example, Yamatoshijimi.

  Furthermore, the system for purifying brackish water according to the present invention comprises a water channel for breeding the filter edible bivalve, having an inlet for the brackish water to flow in and an outlet for discharging the brackish water, and the brackish water from the inlet. Supply means for supplying to the water channel, and the supply device has adjusting means for adjusting the flow rate of the brackish water supplied to the water channel. Here, the adjusting means reduces the depth of water in the water channel. At this time, the depth of water is preferably 10 cm or less, and more preferably 5 cm or less.

  The water channel is made of, for example, concrete or covered with a water-impervious sheet, and further, sand is not laid as a bottom material.

  In addition, the filter edible bivalve is Yamatoshijimi.

  According to the present invention, it is possible to efficiently breed filtered edible bivalves. Furthermore, according to the present invention, brackish water can be purified efficiently using the water purification function of the filter edible bivalve.

  In order to improve the sediment environment, attempts were made to remove the sediment excreted by the filterable bivalve mollusc, but Yamato Shijimi, a filterable bivalve bivalve, generally has the habit of diving in the sand. Therefore, it is very difficult to separate the deposit from the sand and to remove the deposit from the sand. Therefore, the present inventors have developed a filter-feeding bivalve rearing system with a water channel that can easily remove sediments and improve the sediment environment, and using this system, particularly in the summer, Invented a method for breeding a filter edible bivalve that allows the filter edible bivalve to grow without thinning. Furthermore, the present inventors have developed a brackish water purification system using the water purification function of a filter edible bivalve that can grow in a water channel, and have also invented a method for purifying brackish water using this system.

  Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings.

== Configuration of filtration food bivalve breeding system ==
In FIG. 1, the schematic of the filtration edible bivalve breeding system 100 demonstrated as one Embodiment of this invention is shown. Examples of the filter edible bivalve 2 that can be bred using this breeding system include, but are not limited to, yamatoshijimi, oysters, scallops, clams, clams, and the like.

  This filtered food bivalve breeding system 100 includes a water channel 10 for breeding a filtered food bivalve in the brackish water 4, a pump 20 as a supply means for supplying brackish water to the water channel 10, and the like.

  The water channel 10 includes an inlet 6 for introducing brackish water and an outlet 8 for discharging the brackish water. The water channel 10 is preferably made of concrete or covered with a water shielding sheet so that it can be easily cleaned and the growth environment of the filter edible bivalve can be easily optimized.

  Also, do not lay sand as the bottom sediment in the waterway. This makes it possible to easily remove deposits such as pseudofeces or attached diatoms that accumulate in the water channel, and to easily adjust the amount of the deposits.

  In the present embodiment, the pump 20 is provided as an example of a supply unit for supplying brackish water to the inlet of the water channel 10. The flow rate of brackish water supplied to the inlet of the water channel 10 can be adjusted by, for example, providing a valve 14 in the flow path from the pump 20 to the water channel 10 and opening and closing the valve.

  Moreover, when the dissolved oxygen in brackish water or sediment falls, an aeration apparatus (not shown) is provided in the water channel 10 and the aeration apparatus is operated to increase the amount of dissolved oxygen. Good.

== How to breed filtered edible bivalves ==
Hereinafter, a method for breeding a filter edible bivalve using the breeding system described above will be described.

  First, before raising the filter edible bivalve, brackish water is supplied to the water channel 10 using the pump 20, and the inside of the water channel 10 is acclimatized with brackish water. At this time, the flow rate of the brackish water supplied to the inlet of the water channel 10 is adjusted using a valve. At this time, it is preferable to adjust so that the water depth of the brackish water in the water channel 10 becomes shallower, for example, 5 cm or less, so that the brackish water supplied from the pump 20 can entrain air, Alternatively, the amount of dissolved oxygen in the deposit can be increased.

Next, the filtered edible bivalve to be bred in the water channel 10 is placed and the breeding is started. At this time, filter feeders bivalves breeding, it is desirable that the initial weight density is discharged into equally waterway 10 such that ^{1kg / m 2 ~2kg / m 2} . In addition, in order to further increase the yield of filtered edible bivalves, a soil conditioner such as oyster shells may be sprayed into the water channel 10 (Japanese Patent No. 3254277).

  When the filter-feeding bivalve is bred for a while, deposits such as pseudofeces or attached diatoms are deposited in the waterway. The depth of the deposit is preferably 3 cm or less so that the water pipe of the filter edible bivalve can easily reach the brackish water flowing over the deposit. This can prevent the inside of the deposit from becoming anaerobic and inhibiting the growth of the filter edible bivalve in the deposit. If the deposit is deposited deeper than 3 cm, remove it or increase the flow rate to wash away.

  Also, it is often preferable to have a flow rate that allows the sediment to be suspended in brackish water, thereby increasing the organic matter that the filter edible bivalve can use as food, resulting in a decrease in sediment.

  By using the filtered edible bivalve rearing system of the present invention as described above, it becomes possible to efficiently breed filtered edible bivalves, and it is also possible to prevent a decrease in the obesity level of the filtered edible bivalves that occurs particularly in summer. Become.

  In addition, when a large amount of filter edible bivalve moribund occurs in a natural brackish water environment or artificial wetland, the cause is often due to a decrease in the obesity of the filter edible bivalve, so the filter edible By using a bivalve rearing system, it is possible to prevent these drowning by preventing a decrease in the obesity level of the filterable bivalve.

== Application to brackish water purification system ==
Conventionally, water purification of brackish water has been performed using the water purification function of filterable bivalves (Morihiro Aizaki, Mitsuko Morioka, Kunio Kiso; basic research on water purification of brackish water using Yamato Shijimi, Water and drainage, vol40, NO.2 (1998)). However, sediments such as feces and pseudofeces excreted by the filter edible bivalve deteriorated the sediment environment, adversely affected the growth of the filter edible bivalve itself, and reduced the obesity of the filter edible bivalve. In particular, it became a cause of summer thinness of the filter edible bivalve, which caused a decrease in the water purification function of the filter edible bivalve in the summer.

  Therefore, in the above-described filtration dietary bivalve rearing system that can prevent a decrease in obesity, especially summer thinness, by passing brackish water through the water channel where the filterable bivalve is maintained, Without being hindered, brackish water can be purified efficiently.

  Hereinafter, the present invention will be specifically described by way of examples. These examples are for explaining the present invention, and do not limit the technical scope of the present invention.

  In this example, Yamatoshijimi was bred using the above-mentioned filter-feeding bivalve breeding system, and the growth status of Yamatoshijimi was evaluated by measuring the degree of obesity of Yamatoshijimi every month. Moreover, the water purification function of Yamatoshijimi was considered together with the growth situation of Yamatoshijimi.

== Test equipment ==
As shown in FIG. 2, the Yamatojimi breeding system used in this test is provided with water channels 40 and 41 and pumps 50 and 51, and the water channels 40 and 41 are constructed wetland 30 (Aizaki) built on the shore of Lake Kansai. Morihiro, Keiko Yamaguchi, Katsumi Fujioka (eds.); Research on growth analysis and carbon budget of Yamatoshijimi using artificial wetland, pp117, Shimane University Aquatic Ecology Engineering Laboratory, 2004). The water channels 40 and 41 had a length of 3.2 m and a width of 50 cm, and each water channel was covered with a water shielding sheet.

== Test method ==
The test produced 6 groups as described in Table 1.

  As described in Table 1, in this test, Yamatoshijimi was discharged into the water channels 40 and 41, and further water was added to the water channel 41 in order to lower the water temperature in the water channel (group 6). As a control, Yamatoshijimi was bred at 1 point (group 4) in Lake Kansai and 3 points in artificial wetland (group 1 to 3).

Brackish water was introduced into groups 1 to 3 and groups 5 and 6, and then Yamatoshijimi was discharged to all groups at a density of 1 kg / m ² to start breeding. In addition, the water temperature of each control group was in the range of 12.7 ° C to 35.0 ° C.

  In order to investigate the change in the soft body weight of Yamatoshijimi, 20 Yamajishijimi of standard size existing in each group were collected once a month. And the obesity degree was computed using the following "determination method of the obesity degree of a filter dietary bivalve", and the average of 20 individuals was computed.

  In groups 5 and 6, after examining the change in soft body weight in September, the change in obesity was measured when the pump was turned off and the brackish water was removed.

== Judgment method of the obesity degree of filtered dietary bivalve ==
In order to determine the degree of obesity of the filter edible bivalve, the filter edible bivalve was collected and the shell length, shell height, shell width, and wet weight of the individual were measured. Subsequently, the soft body part of the filter edible bivalve was taken out and the soft body part weight was measured. Thereafter, the soft body part was dried for 3 days, and the dry weight of the soft body part was measured. The degree of obesity was calculated using the following formula.
Obesity degree (%) = soft body dry weight (g) / shell length (cm) × shell height (cm) × shell width (cm)
It was judged that the greater the calculated degree of obesity, the more the filter-feeding bivalve is obese.

== Result ==
As shown in FIG. 3, Yamato Shijimi bred in a waterway according to the present invention has no decrease in obesity level from August to September 2004 (the obesity level is maintained at about 0.025 to 0.03%) and is flat. (Water channel reed group) or a slight increasing tendency (water channel control group) was observed. However, from September to October, when the pump was switched off and the inflow of brackish water was eliminated, the degree of obesity decreased greatly. This suggests that inflow and outflow of brackish water is necessary to prevent a decrease in obesity in the waterway.

  From the above results, it became clear that summer thinning of Yamatoshijimi can be prevented by using the method for breeding filtered edible bivalves of the present invention.

  Accordingly, the filtered food bivalve rearing system of the present invention can maintain the bottom sediment environment well even in the summer when the bottom sediment environment is expected to deteriorate, thus preventing summer thinness of the filter diet bivalve. Therefore, it is possible to efficiently breed filtered edible bivalves, and to prevent drowning of filtered edible bivalves that are likely to occur in summer. As a result, the water purification function of the filter edible bivalve can be effectively exhibited, and brackish water can be purified efficiently.

It is a mimetic diagram showing the outline of the breeding system of the filtration edible bivalve in one embodiment of the present invention. It is a model drawing which shows the structure of the breeding system of the filter edible bivalve in the Example of this invention. It is the graph which calculated the obesity degree of Yamatojimi every month, and showed the result.

Explanation of symbols

2 Filtration edible bivalve 4 Brackish water 6 Inlet 8 Exit 10 Water channel 12 Sediment 14 Valve 20 Pump 100 Filtration edible bivalve breeding system 30 Artificial wetland 40, 41 Water channel 50, 51 Pump

Claims (33)

It is a breeding method to prevent summer thinness of filtered food bivalve,
A breeding method comprising a step of breeding the filtered edible bivalve while flowing brackish water into a waterway.   The breeding method according to claim 1, wherein the deposit deposited in the water channel is set to several cm or less.   The breeding method according to claim 1 or 2, wherein the water depth of the water channel is reduced.   The breeding method according to any one of claims 1 to 3, wherein sand is not laid as bottom sediment in the water channel.   The breeding method according to claim 1, wherein the water channel is made of concrete.   The breeding method according to claim 1, wherein the water channel is covered with a water shielding sheet.   The breeding method according to any one of claims 1 to 6, wherein the filtered edible bivalve is Yamatoshijimi. A method for breeding filtered edible bivalves,
A breeding method comprising a step of breeding the filtered edible bivalve while flowing brackish water into a water channel.   The breeding method according to claim 8, wherein the deposit deposited in the water channel is set to several cm or less.   The breeding method according to claim 8 or 9, wherein the water depth of the water channel is reduced.   The breeding method according to any one of claims 8 to 10, wherein sand is not laid as bottom sediment in the water channel.   The breeding method according to claim 8, wherein the water channel is made of concrete.   The breeding method according to claim 8, wherein the water channel is covered with a water shielding sheet.   14. The breeding method according to any one of claims 8 to 13, wherein the filter-feeding bivalve is Yamatoshijimi.   A method for purifying brackish water, comprising a step of allowing brackish water to pass through a water channel for breeding filtered edible bivalves.   The purification method according to claim 15, wherein a deposit deposited in the water channel is set to several cm or less.   The breeding method according to claim 15 or 16, wherein the water depth of the water channel is reduced.   The purification method according to any one of claims 15 to 17, wherein sand is not laid as a bottom material in the water channel.   The purification method according to claim 15, wherein the water channel is made of concrete.   The purification method according to claim 15, wherein the water channel is covered with a water shielding sheet.   The purification method according to any one of claims 15 to 20, wherein the filterable bivalve molluscs are Yamatoshijimi. A system for breeding filtered edible bivalves,
A water channel for breeding the filtered edible bivalve, with an inlet for brackish water inflow and an outlet for discharge;
Supply means for supplying the brackish water to the water channel from the inlet;
The supply means is a system having adjustment means for adjusting the flow rate of brackish water supplied to the water channel.   The system according to claim 22, wherein the adjusting means reduces the depth of water in the water channel.   24. System according to claim 22 or 23, characterized in that the water channel is not laid with sand as a bottom.   The system according to any one of claims 22 to 24, wherein the water channel is made of concrete.   The system according to any one of claims 22 to 24, wherein the water channel is covered with a water shielding sheet.   27. The system according to any one of claims 22 to 26, wherein the filter edible bivalve is Yamatojimi. A system for purifying brackish water,
A water channel for breeding the filtered edible bivalve, with an inlet for brackish water inflow and an outlet for discharge;
Supply means for supplying the brackish water to the water channel from the inlet;
The supply means is a system having adjustment means for adjusting the flow rate of brackish water supplied to the water channel.   The system according to claim 28, wherein the adjusting means reduces the depth of water in the water channel.   30. System according to claim 28 or 29, characterized in that the water channel is not laid with sand as bottom sediment.   The system according to any one of claims 28 to 30, wherein the water channel is made of concrete.   The system according to any one of claims 28 to 30, wherein the water channel is covered with a water shielding sheet. The system according to any one of claims 28 to 32, wherein the filter edible bivalve is Yamato Shijimi.

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